Abstract
Introduction
To evaluate the results of correction of knee deformities based on deformity analysis in Achondroplasia, the commonest skeletal dysplasia as some have concomitant ligamentous deformities
Materials and Methods
Retrospective study from a prospective database (2007–2020) of achondroplasts who underwent growth modulation. Analysis of medical records with objective measurement of mechanical axis radiographs was done (Traumacad). Satisfactory alignment was defined as neutral to slightly varus (0–15 mm MAD) so that the MCL/LCL laxity is not revealed.
Results
23 patients, 41 limbs, 34 bilateral, 6 unilateral underwent multiple growth modulation procedures. 2 had valgus knees. 15 patients underwent proximal fibular epiphysiodesis in addition for LCL laxity with one isolated fibular epiphysiodesis.
Mechanical axis deviation (MAD) improved or normalised in 16 patients (70%). 4 patients were still undergoing correction. 4 patients needed further surgery out of which 2 patients were over 13 years when growth modulation was attempted and 2 needed correction of ankle varus. JLCA improved/ normalised in 12 patients (75%) with evidence of indirect LCL tightening and no improvement was seen in 4. The rate of correction was MAD 0.61mm/month, LDFA 0.29°/month and MPTA 0.13°/month; expectedly lower in achondroplasia due to lower growth velocity
Conclusions
This study highlights the pathology, application of growth modulation as per deformity analysis unlike previous studies. Proximal fibular epiphysiodesis improves LCL laxity in a majority of these children and is a simple procedure compared to our published series with indirect LCL tightening with frames.
